The Tisa is a major international river and the largest tributary of the Danube, flowing through four countries. Its total length is 966 km, with 164 km passing through Serbia. The river originates in the Carpathians at an altitude of 1,800 meters, but after 266 km of its upper course, near the mouth of the Samoš, it descends to just above 200 meters, gradually sloping to its confluence with the Danube.
